Yes, fen is a Scrabble word!
...and is worth 6 points in Scrabble, and 7 points in Words with Friends
fen
Noun
1. 100 fen equal 1 yuan in China
2. Low-lying wet land with grassy vegetation; usually is a transition zone between land and water
What Scrabble words can I make with the letters in fen?
2 Letter Words